1. Field of the Invention
The present invention relates to a hard disk drive, and more particularly to an actuator crash stopper in a hard disk drive.
2. Description of the Related Art
Generally, the hard disk drive is a magnetic storage device consisting of electronic and mechanical devices, which converts the digital electrical pulse into permanent magnetic field so as to record data on the disk surface.
A typical hard disk drive suitable for use with a microcomputer or CPU (Central Processing Unit), is constructed with a generally, rectangularly shaped base serving as a frame providing a major interior surface accommodating a plurality of circular disks coaxially mounted in a stack upon a spindle driven by a motor mounted on the base to provide a plurality of cylindrical base surfaces that serve as a memory into which binary information may be written and read. An actuator, mounted upon the base by a pivot, freely rotates about the longitudinal axis of the pivot as controlled by a voice coil motor positioned to respond to electrical control signals and thereby arcuately displace a proximal end of the actuator arm. The actuator arm supports a head gimbal at its distal end which, in turn, supports a plurality of electromagnetic transducers commonly known as read/write actuator heads for reading and writing data on the disks. A PCBA (Printed Circuit Board Assembly) controls the disk drive components, and an interface is connected between the disk drive and the CPU. Typically, the base surfaces of the disks are coated with a magnetically sensitive material that responds to fields created by corresponding ones of the heads, to enable the heads to either write bits of information at selected locations along tracks formed on the surface of the disk, or to read information from those tracks. Generally, the disks continuously rotate in a single direction while the voice coil motor acts upon the proximal end of the actuator arm to arcuately displace the proximal end relative to the motor and thereby cause the distal ends of the actuator arm to radially position the heads along corresponding base surfaces of the disks to read or write data thereto.
The actuator heads "fly" over the corresponding base surfaces of the disks, and are normally spaced apart from those surfaces by a hydrodynamic air bearing formed by a cushion of air generated by the rapid rotation of the disks. The voice coil motor drives the proximal end of the actuator arm to move the heads to a data free parking or landing zone of the disks upon which the heads may rest without destroying information stored on the disks, when electrical power is turned off. Typically, the actuator arm quickly moves the heads to the parking zone in case of error or loss of power, and generally a crash stop is provided to block the proximal end and thereby limit further movement of the actuator arm once the heads reach their stop position within the parking zone. Examples of hard disk drives having crash stops are U.S. Pat. No. 5,187,627 to Thomas A Hickox et al. entitled Magnetic Latch And Crash Stop; U.S. Pat. No. 5,365,389 to Iraj Jabbari et al. entitled Crash Stop And Magnetic Latch For Optimum Use Of Disc Space; and U.S. Pat. No. 5,712,750 to Youn-Tai Kim entitled Actuator Fixing Device Of Hard Disk Drive.